Screening of endophytic bacteria by protection against water deficit in peanut plants

ESPINOSA HERLEIN, MARIA DE LOS ANGELES; RUIZ, OA; GUZZO, MC; MONTEOLIVA, MI

Rosario

Congreso; Reunion Argentina de Fisiologia Vegetal; 2023

One of the most frequent and damaging environmental stresses worldwide is drought or water deficit. Drought can reduce photosynthesis rates, inhibit growth, and cause yield and grain quality drops in crops. To reduce the losses by drought, we aim to find beneficial bacteria able to protect peanut plants against the negative effects of stress. Endophytic bacteria are microbes that colonize and proliferate inside the plant tissues without causing any damage. They colonize mostly the intercellular space. Previously we classified 76 bacteria isolates from peanut crop, according to their osmotic tolerance in vitro. This project aimed to classify endophytic bacteria from peanuts according to their protective effect against drought in vivo. We carried out greenhouse experiments in peanut plantlets (the commercial Granoleico cultivar). We inoculated the seedlings and then sprayed the leaflets two more times before the drought onset. Then we started the water deficit by reducing the irrigation. We kept plants uninoculated plants, both under drought and sufficient irrigation, as controls. When soil moisture reached 15% of the maximum soil water content, physiological responses (such as relative water content -RWC- and leaf temperature as transpiration marker) and total shoot biomass were measured. We observed variability in the evaluated responses. RWC varied between 50 and 75% (water deficit controls showed 60% as average). We also found variability in transpiration and biomass accumulation. Till the moment, we have one isolate with RWC over 70% and a higher transpiration rate than uninoculated controls, which is a strong candidate for further characterization.